AU2007293146A1

AU2007293146A1 - Explosive

Info

Publication number: AU2007293146A1
Application number: AU2007293146A
Authority: AU
Inventors: Derek Luke Anthony; Dave Alfred Tyler; Charl Vermaak
Original assignee: African Explosives Ltd
Current assignee: AEL Mining Services Ltd
Priority date: 2006-09-04
Filing date: 2007-09-03
Publication date: 2008-03-13
Anticipated expiration: 2027-09-03
Also published as: PL2069266T3; AP2009004800A0; ZA200901785B; WO2008029339A3; CL2007002539A1; AP2766A; CA2662067A1; WO2008029339A2; PE20080485A1; EP2069266A2; EP2069266B1; BRPI0714743A2; DK2069266T3; AR062641A1; AU2007293146B2

Description

WO 2008/029339 PCT/IB2007/053534 1 EXPLOSIVE THIS INVENTION relates broadly to ammonium nitrate/fuel oil explosive, also known as ANFO explosive, and hereinafter referred to as ANFO explosive. More 5 particularly, the invention relates to a process for producing an ANFO explosive, and to an ANFO explosive when produced in accordance with the process. According to the invention, broadly, there is provided a process for producing an ammonium nitrate fuel oil (ANFO) explosive, the process including: 10 admixing an oil with water to form a fuel comprising an emulsion; and admixing the emulsion with solid particulate ammonium nitrate to absorb the emulsion into the ammonium nitrate to form an ANFO explosive. In a preferred embodiment of the invention, the oil is used lubricating oil. 15 More particularly, the lubricating oil may be of the type employed for the lubrication of motor vehicles, such as utility vehicles of the kind used in mines, or for the lubrication of similar machinery. The particulate ammonium nitrate in turn will typically be in the form of porous prills of the type conventionally used for the manufacture of 20 ANFO explosives. The relative proportions of emulsion and ammonium nitrate employed will be more or less conventional, such that, in the product ANFO explosive, the oil forms 5-8% by mass, typically 5-7% by mass, e.g. 6% thereof. In the emulsion, the oil may 25 form 55-86% by mass, preferably 72-78% by mass, e.g. 75% thereof. The balance is thus naturally water. Thus, when the oil forms 75% by mass of the emulsion, water forms 25% by mass thereof. The emulsion may thus be either a water-in-oil emulsion or an oil-in-water 30 emulsion, depending on, amongst others, the relative proportions of oil and water used. Admixing the oil with the water to form the emulsion may be by means of high-shear mixing, eg by using a high-shear mixer. The admixing may be effected in WO 2008/029339 PCT/IB2007/053534 2 the presence of a suitable emulsifier/surfactant, which may form 0.2-1.0% by mass of the emulsion, preferably 0.3-0.8%, e.g. 0.5% thereof. While all of the emulsifier/surfactant can be added to the oil, to the water 5 and/or to an oil/water mixture, at least a portion of the emulsifier/surfactant may already be present in the oil, so that, at most, only any shortfall in the emulsifier/surfactant is then added to the oil, to the water or to the oil/water mixture. Admixing the emulsion with the porous prilled ammonium nitrate (PPAN) 10 may be in conventional fashion by pumping the emulsion from a source tank and spraying it by means of a nozzle on to the ammonium nitrate which is moved along by the flutes of an auger to provide additional mixing. To prepare the ANFO explosive on a batch scale, a concrete mixer or the like may be used. A PPAN:fuel ratio of 95:5-85:15, preferably 94:6-91:9, e.g. 92:8, may be used. 15 The invention extends also to an ANFO explosive when produced in accordance with the process described herein. The invention will now be described, by way of example, with reference to 20 the accompanying non-limiting illustrative worked Example. EXAMPLE Mine utility vehicle waste lubricating oil was mixed in a high-shear mixer 25 with water using an emulsifier/surfactant, to form a water-in-oil emulsion. The mixer used was an off-the-shelf mixer marketed under the trade designation Jones Industrial Mixer by Jones Process Equipment as manufacturer; and the emulsifier/surfactant used was an off-the-shelf sorbiton monooleate made by Croda Chemicals (SA) (Pty) Limited, 4 Covora Street, Jet Park, PO Box 1642, 1620 Kempton Park, South Africa. After 30 mixing the oil and water into a stable homogeneous emulsion, comprising 0.5% by mass emulsifier/surfactant, 24.5% by mass water and 75% by mass oil, the emulsion was admixed with PPAN by pumping the emulsion from a source tank and spraying it by means of a nozzle on to the ammonium nitrate prills which were moved along by the WO 2008/029339 PCT/IB2007/053534 3 flutes of an auger to provide additional mixing, to cause absorption of the emulsion into the PPAN, in a PPAN:emulsion mass ratio of 92:8. The emulsion was found to be absorbed almost immediately into the PPAN to form an ANFO explosive. 5 The ANFO explosive was subjected to detonation tests in comparison with standard ANFO explosive made from PPAN and a fuel comprising Shellsol 2325 (trademark) mining solvent, and was found to behave in comparable fashion as far as plate detonation tests and velocity of detonation (VOD) were concerned. 10 The Applicant is aware that used mine utility vehicle oil, which is generated in large volumes, has been used in the past for the manufacture of ANFO explosive. However, it is refractory and difficult to absorb into PPAN by itself, so that it must be diluted with diesel or other virgin oil, such as the mining solvent available in South Africa under the trade mark Shellsol 2325 from Shell South Africa Energy (Pty) 15 Limited of Shell Court, 33 Baker Street, Rosebank 2196, PO Box 747, Saxonwold 2132, South Africa. When the ANFO explosive comprises, as is typically the case, 5-7% by mass fuel oil, the balance being PPAN, no more than about 2-3% of the ANFO explosive can be waste mine utility vehicle oil, the remaining 3-4% being required to be virgin diesel or Shellsol. This is a disadvantage, because of the cost of the virgin oil, 20 and because of the lowered consumption of used or waste oil. It is thus a particular advantage of the present invention that it obviates the use of any virgin oil to dilute the waste oil, the virgin oil being supplanted by water and economically attractive small amounts of emulsifier/surfactant. Disposal in this fashion of the waste oil is thus ecologically desirable and economically attractive.

Claims

1. A process for producing an ammonium nitrate fuel oil (ANFO) explosive, the process including: 5 admixing an oil with water to form a fuel comprising an emulsion; and admixing the emulsion with solid particulate ammonium nitrate to absorb the emulsion into the ammonium nitrate to form an ANFO explosive.

2. A process according to Claim 1, wherein the oil is used lubricating oil. 10

3. A process according to Claim 2, wherein the used lubricating oil is that obtained from mining vehicles.

4. A process according to any one of Claims 1 to 3 inclusive, wherein the 15 solid particulate ammonium nitrate is in the form of porous prills.

5. A process according to any one of Claims 1 to 4 inclusive, wherein the relative proportions of emulsion and ammonium nitrate employed are such that, in the ANFO explosive, the oil forms 5-8% by mass thereof. 20

6. A process according to any one of Claims 1 to 5 inclusive wherein, in the emulsion, the oil forms 55-86% by mass thereof.

7. A process according to any one of Claims 1 to 6 inclusive, wherein high 25 shear mixing is used to effect the admixing of the oil with the water to form the emulsion.

8. A process according to any one of Claims 1 to 7 inclusive, which includes effecting the admixing of the oil with the water to form the emulsion, in the presence of 30 an emulsifier/surfactant.

9. A process according to Claim 8, wherein the emulsifier/surfactant forms 0.2-1.0% by mass of the emulsion. WO 2008/029339 PCT/IB2007/053534 5

10. A process according to Claim 9, wherein the emulsion/surfactant forms 0.3-0.8% by mass of the emulsion. 5

11. A process according to any one of Claims 1 to 10 inclusive, wherein the admixing of the emulsion with the particulate ammonium nitrate is by pumping the emulsion from a source tank and spraying it by means of a nozzle on to the particulate ammonium nitrate which is moved along by the flutes of an auger to provide additional mixing, in an ammonium nitrate:emulsion ratio of 95:5-85:15. 10

12. An ANFO explosive when produced in accordance with the process of any one of Claims 1 to 11 inclusive.